The first book in the Jackson Brodie series, 2004

How lucky were they? A heat wave in the middle of the school holidays, exactly where it belonged. Every morning the sun was up long before they were, making a mockery of the flimsy summer curtains that hung limply at their bedroom windows, a sun already hot and sticky with promise before Olivia even opened her eyes. Olivia, as reliable as a rooster, always the first to wake, so fiat no one in the house had bothered with an alarm clock since she was born three years ago.

Olivia, the youngest and therefore the one currently sleeping in the small back bedroom with the nursery-rhyme wallpaper, a room that all of them had occupied and been ousted from in turn. Olivia, as cute as a button they were all agreed, even Julia, who had taken a long time to get over being displaced as the baby of the family, a position she had occupied for five satisfying years before Olivia came along.

Rosemary, their mother, said that she wished Olivia could stay at this age forever because she was so lovable. They had never heard her use that word to describe any of them. They had not even realized that such a word existed in her vocabulary, which was usually restricted to tedious commands: come here, go away, be quiet, and – most frequent of all – stop that. Sometimes she would walk into a room or appear in the garden, glare at them, and say, Whatever it is you're doing, don't, and then simply walk away again, leaving them feeling aggrieved and badly done by, even when caught red-handed in the middle of some piece of mischief- devised by Sylvia usually.

Their capacity for wrongdoing, especially under Sylvia's reckless leadership, was apparently limitless. The eldest three were (everyone agreed) "a handful," too close together in age to be distinguishable to their mother so that they had evolved into a collective child to which she found it hard to attribute individual details and which she addressed at random -Julia-Sylvia-Amelia-whoever you are - said in an exasperated tone as if it were their fault there were so many of them. Olivia was usually excluded from this weary litany; Rosemary never seemed to get her mixed up with the rest of them.

They had supposed Olivia would be the last of the four to occupy the small back bedroom and that one day the nursery-rhyme wallpaper would finally be scraped off (by their harassed mother because their father said hiring a professional decorator was a waste of money) and be replaced by something more grown-up – flowers or perhaps ponies, although anything would be better than the Elastoplast pink adorning the room that Julia and Amelia shared, a color that had looked so promising to the two of them on the paint chart and proved so alarming on the walls and which their mother said she didn't have the time or money (or energy) to repaint.

Now it transpired that Olivia was going to be undertaking the same rite of passage as her older sisters, leaving behind the – rather badly aligned – Humpty Dumptys and Little Miss Muffets to make way for an afterthought whose advent had been announced, in a rather offhand way, by Rosemary the previous day as she dished out on the lawn a makeshift lunch of corned beef sandwiches and orange squash.

"Wasn't Olivia the afterthought?" Sylvia said to no one in particular, and Rosemary frowned at her eldest daughter as if she had just noticed her for the first time. Sylvia, thirteen and until recently an enthusiastic child (many people would have said overenthusias-tic), promised to be a mordant cynic in her teenage years. Gawky, bespectacled Sylvia, her teeth recently caged in ugly orthodontic braces, had greasy hair, a hooting laugh, and the long, thin fingers and toes of an alien from outer space. Well-meaning people called her an "ugly duckling" (said to her face, as if it were a compliment, which was certainly not how it was taken by Sylvia), imagining a future Sylvia casting off her braces, acquiring contact lenses and a bosom, and blossoming into a swan. Rosemary did not see the swan in Sylvia, especially when she had a shred of corned beef stuck in her braces. Sylvia had recently developed an unhealthy obsession with religion, claiming that God had spoken to her (as if God would choose Sylvia). Rosemary wondered if it was a normal phase that adolescent girls went through, if God was merely an alternative to pop stars or ponies. Rosemary decided it was best to ignore Sylvia's tete-a-tetes with the Almighty. And at least conversations with God were free, whereas the upkeep on a pony would have cost a fortune.

And the peculiar fainting fits that their GP said were on account of Sylvia "outgrowing her strength" – a medically dubious explanation if ever there was one (in Rosemary's opinion). Rosemary decided to ignore the fainting fits as well. They were probably just Sylvia's way of getting attention.

Rosemary married their father, Victor, when she was eighteen years old – only five years older than Sylvia was now. The idea that Sylvia might be grown-up enough in five years' time to marry anyone struck Rosemary as ridiculous and reinforced her belief that her own parents should have stepped in and stopped her from marrying Victor, should have pointed out that she was a mere child and he was a thirty-six-year-old man. She often found herself wanting to remonstrate with her mother and father about their lack of parental care, but her mother had succumbed to stomach cancer not long after Amelia was born, and her father had remarried and moved to Ipswich, where he spent most of his days in the bookies and all of his evenings in the pub.

If, in five years' time, Sylvia brought home a thirty-six-year-old, cradle-snatching fiance (particularly if he claimed to be a great mathematician), then Rosemary would probably cut his heart out with the carving knife. This idea was so agreeable that the afterthought's annunciation was temporarily forgotten and Rosemary allowed them all to run out to the ice-cream van when it declared its own melodic arrival in the street.

The Sylvia-Amelia-Julia trio knew that there was no such thing as an afterthought, and the "fetus," as Sylvia insisted on calling it (she was keen on science subjects), that was making their mother so irritable and lethargic was probably their father's last-ditch attempt to acquire a son. He was not a father who doted on daughters, he showed no real fondness for any of them, only Sylvia occasionally winning his respect because she was "good at maths." Victor was a mathematician and lived a rarefied life of the mind, where his family was allowed no trespass. This was made easy by the fact that he spent hardly any time with them. He was either in the department or his rooms in college, and when he was home he shut himself in his study, occasionally with his students but usually on his own. Their father had never taken them to the open-air pool on Jesus Green, played rousing games of Snap or Donkey, never tossed them in the air and caught them or pushed them on a swing, had never taken them punting on the river or walking on the Fens or on educational trips to the FitzwiUiam. He seemed more like an absence than a presence: everything he was – and was not – was represented by the sacrosanct space of his study.